In a conventional open-end wrench, a rigid jaw is joined to a shank. The jaws have parallel faces that slide over the sides of the nut. After each stroke, the user must remove the wrench from the nut and reposition it on the nut. Typically the nut is hexagonal, with a point or corner every 60.degree.. Because of the necessary clearances required to fit the wrench over the nut, the wrench actually contacts the nut at the corners. This to round the corners of the nut, particularly when high torque is required.
A number of patents have issued disclosing open-end wrenches that will ratchet. That is, the user is able to reposition the wrench on the nut for another stroke without having to completely remove the wrench from the nut. The designs have various deficiencies. Many of them drive only on the corners of the nut, tending to round the corners off. They also usually require that the wrench be pulled away from the nut with each repositioning stroke so that the next position is not self-seeking. A wrench that is self seeking has the characteristics of ratcheting from one driving position to the next while being held in contact with the nut. This self seeking characteristic would be due entirely to the design of the various surfaces, faces, points and angles of the wrench in relation to the nut to be turned, and would not require special positioning of the wrench by the user.
Another problem with prior art wrenches is that there is the potential for the wrench to slide off the nut during torque. This is particularly true when high torque is being applied. When this occurs, the user may scrape or injure his hand, particularly when the wrench is being used in confined areas. Notches formed in the drive faces in non-ratcheting-type wrenches have been used in the past to hold the wrench in place on the nut during torque, but not in a 60.degree. self-seeking ratchet-type wrench, or even more particularly, in a60.degree. self-seeking ratchet-type wrench that also has a 30.degree. incremental drive function. Many of the prior art ratcheting wrenches must also drive the nut with the wrench full engaging the nut. This may become a problem when space constraints prevent the full wrench head from fitting around the nut.